346 THE FUNGI WHICH CAUSE PLANT DISEASE 



scure; paraphyses hyphoid, very delicate, collapsing, 60-80 m 

 long, wall colorless, very thin, slightly thickened at apex, 1 m- 



III. Telia, unknown. 



II. On fig and osage orange. 



Pucciniastrum Otth. (p. 341) 



Heteroecious. The cycle of development includes pycnia, secia, 

 uredinia and telia, with distinct alternating phases. 



0. Pycnia subcuticular, low-conoidal, without ostiolar filaments. 



1. ^cia erumpent, cylindrical. Peridium delicate, verrucosa 

 on inner surface. Spores ellipsoid, verrucose except one side which 

 is thinner and smooth. 



II. Uredinia barely protruding through the epidermis, dehis- 

 cent by a central pore. Peridium hemispherical, delicate, cells 

 longer at orifice. Spores borne singly on pedicels, obovate to 

 ellipsoid; wall colorless, echinulate, pores indistinct. 



III. Telia indehiscent, forming more or less evident layers in 

 the epidermal cells or immediately beneath the epidermis. Spores 

 oblong or prismatic, 2 to 4-celled by vertical partitions in two 

 planes; wall smooth, colored. 



Arthur*' lists nine American species but none are very impor- 

 tant. 

 P. hydrangese (B. & C.) Arth. 

 and I. Unknown. 



II. Uredinia hypophyllous, scattered, round, small, 0.1-0.2 mm. 

 across, dark-yellow fading to pale-yellow, ruptured epidermis 

 inconspicuous, dehiscent by a central pore; peridium hemispher- 

 ical, delicate, cells small, cuboid, walls uniformly thin, 1-1.5 n, 

 ostiolar cells slightly or not elongate, 10-16 n, barely pointed, 

 walls thin, smooth; spores broadly elliptical or obovate, 12-18 

 X 16-24 fi; wall nearly colorless, thin, 1-1.5 fi, sparsely and 

 strongly echinulate. 



III. Telia amphigenous, or chiefly epiphyllous, effused, or 

 confluent into small angular groups, 0.3-0.8 mm. across, not 

 raised, reddish-brown; spores forming a single layer within the 

 epidermal cells, or sometimes between the epidermis and mes- 

 ophyll, globoid, 22-28 x 24-28 /*, wall dark cinnamon-brown, 

 uniformly thin, 1.6-2 n. 



